Streptococcus suis

Streptococcus suis is a species of bacterium found in many parts of the world where pigs are raised. It is most adapted to domesticated pigs, but is also occasionally found from wild boars, horses, dogs, cats and birds. Human infection was first described in the 1960s and is increasingly recognized. Infection in pigs is usually asymptomatic, but can result in septicaemia (blood poisoning), meningitis, pneumonia and arthritis.

The most important risk factor in acquiring the infection is contact with pigs or uncooked pig products, typically farmers, veterinary personnel, abattoir workers and butchers are the risk groups. Transmission to humans is most likely to occur through wounds on the skin, including minor abrasions. The incubation period ranges from a few hours up to three days. Classically, infection in humans produces a fever and signs of meningitis (headache, vomiting, neck stiffness, intolerance of light and decreased level of consciousness). Hearing loss, which is generally permanent and affects around 50% of those infected, occurs due to involvement of the auditory nerve. Arthritis and pneumonia are also possible complications. Prevention of the disease in humans depends upon control in pig populations. Those with open wounds should wear gloves when handling raw or uncooked pork, and all those who prepare pork should wash their hands and clean their utensils thoroughly after preparation. Adequate cooking is also essential.